Today I realised another problem that plagues me in Czech. I have a new Czech student who I speak to in English during lessons but who yesterday started to spek to me in Czech outside of the lesson. I had been teaching her for 4 days but I didn't know whether I should jump straight into tykani or go for vykani. I know native speakers usually suggest it to each other in this type of situation before using tykani. This has been a regular problem for me in my time as a teacher of Czechs. I feel like if I use vykani then I'm saying that we are not friends and maybe it would affect the classroom chemistry (mainly conversation class) and if I use tykani (which I did and usually do) then maybe I'm being disrespectful and offensive. Kind of like if I said to a new business colleague in English - 'alwight mate, how ya doin, wot you bin up to this week?' It would feel inappropriate. How do Czechs feel when they hear foreigners using tykani when they should be using vykani or vice-versa? I mean foreigners with a Upper-Int to Advanced level?